Kansas chemical blast may spur safety steps

Tim Potter, The Wichita Eagle, Kan. On Feb 3, 2008
Source: LexisNexis

Feb. 3--The massive Barton Solvents explosion in Valley Center last July could prompt a national safety advisory for facilities that transfer and store certain flammable liquids, a federal investigator says.

The advisory, if approved by the U.S. Chemical Safety and Hazard Investigation Board, would urge handlers nationwide to take a series of precautions.

They would include measures to prevent the accumulation of static electricity -- which was blamed for the explosion -- and a step to eliminate a key component in a fire -- oxygen in storage tanks.

"We're going to use the Barton incident as our example of what can go wrong and how it could have been prevented," said Randy McClure, the safety board's lead investigator on the Valley Center incident.

"We think there are similar businesses vulnerable to this same type of accident," McClure said.

The advisory could be issued in March or April.

The advisory would be for any facilities that pump and store flammable solvents, as defined by National Fire Protection Association standards.

Meanwhile, a top Barton Solvents official says the company will be testing a system that removes oxygen from storage tanks. That system could be used when the company rebuilds its Valley Center tank farm or moves to Bel Aire or some other location in Sedgwick County. The system would be among the steps recommended in the safety advisory.

A recently completed state investigation has concluded that the July 17 explosion occurred when a static electric charge ignited vapors in a solvent tank that was being filled. Since the incident, officials have said they suspected static in the tank.

For an explosion to occur three conditions must be present: an ignition source, fuel and oxygen. Removing any one of the elements greatly decreases the chance of a fire.

Possible causes

The 54-page state report, compiled by state fire investigator Dave Higday and obtained last week by The Eagle, lists possible contributing factors in the tank explosion, among them:

- The liquid's natural tendency to accumulate a static charge.

- A lack of additives to reduce static.

- A nearly empty storage tank that could have caused the liquid to splash when the tank was being filled. Agitation can generate static.

- Air being pushed into the tank from a pump that continued to run. That could have agitated the tank contents and increased the ignitable mixture.

- How fast the liquid was being pumped. A higher velocity can create more static.

The explosion launched the 10 1/2 -foot-wide, 24-foot-tall tank far enough into the air that when it landed on plant property, it nearly collapsed, Higday said.

Other explosions and flames engulfed the tank farm, creating smoke that was visible for miles. No one was injured, but authorities urged Valley Center residents to evacuate.

Asked about the potential for harm that day, Higday said, "We had debris that went 200 to 300 yards. If it would have hit somebody, they would have been dead... or seriously injured."

One tank's top struck the corner of a mobile home near the tank farm. The residents weren't home. Another heavy piece struck the metal building of a nearby business.

Barton Solvents, which is weighing whether to re-open in Valley Center or elsewhere in the county, will be testing a costly safety measure that could prevent another such explosion, said company president Dave Casten.

The measure involves pumping nitrogen into above-ground storage tanks to deplete the oxygen around the flammable liquid. Without oxygen, a fire or explosion is much less likely to occur.

Nitrogen blanketing, as it is called, is one of three safety steps among the recommendations in a draft of the national safety advisory, said McClure, the safety board investigator. The advisory is being prepared by the investigative team led by McClure.

The advisory would come first; then around July, McClure and the team expect to complete a combined investigative report on the Valley Center incident and another Barton Solvents fire in Des Moines. The Iowa fire involved a portable tank being filled at a warehouse, McClure said.

The advisory would target a class of flammable liquids that give off ignitable vapors even under normal conditions and build their own static charge.

The product in the tank that exploded had the brand name Special Naphtholite 66/3, more commonly referred to in the industry as VM&P naphtha. McClure described it as a common solvent that has been used in the paint industry for years.

Besides recommending that nitrogen be used, the advisory would also outline other safety practices including using anti-static additives in the "bad-actor" solvents and slowing the velocity at which liquids are pumped into tanks, McClure said. If liquid goes into a tank at too high a rate, it can increase static, increasing the likelihood of an explosion.

"If you do any one of them, you could greatly lessen the chance of an event like this," he said.

In the state investigation, Higday reported that Barton officials said they didn't use anti-static additives because customers would have to agree to the practice and because the absence of additives had not caused a problem.

The state's investigative report also raised the question of whether the pump being used to transfer solvent from a tanker-trailer into the storage tank was pumping too fast.

Casten, the Barton Solvents president, said additives aren't widely used and said the pump speed fell within guidelines.

The state report noted that the experienced Barton Solvents dock foreman who was filling the tank said he "didn't do anything different" that day. Barton Solvents has owned the site since 1979 and has operated in Valley Center without a similar incident.

County tank inspections

Because of the explosion, Sedgwick County would probably consider requiring a nitrogen blanketing system for any new, similar facility, said Sedgwick County Fire Marshal Tim Millspaugh.

Millspaugh, Casten and other officials -- including Bob Benedetti, a flammable-liquids expert with the National Fire Protection Association, which sets safety codes and standards -- agreed that nitrogen blanketing is not widely used largely because of the cost. Casten said the cost is "six-figure" per facility for equipment and installation.

But even if the cost exceeds $100,000 a year, "it's better than a 20 or 30 million-dollar fire every 10 or 15 years," Millspaugh said. "If I were a plant owner, that's the way I would look at it."

Casten declined to discuss damage figures.

This year, the county's fire department plans to train at least two people to inspect above-ground storage tanks in the county fire district, Millspaugh said.

"That's not to say that an inspection would have prevented the Valley Center thing," Millspaugh said.

Still, inspectors could check for such features as grounding equipment to help prevent fires and explosions and dikes to contain material, he said.

The county would not inspect in Valley Center because the city has its own fire department and is outside the fire district, Millspaugh said.

Valley Center would rely on the state fire marshal's office for tank inspections, said Kristine Polian, the city clerk. The city's fire department doesn't have the personnel and expertise to do the job, she said.

The state fire marshal's office has said it never inspected Barton' 43-vessel tank farm because it lacks staffing and the expertise.

Next step for Barton

Before the explosion, Casten said, Barton Solvents thought it had enough safeguards in place, including adequate grounding. Grounding is designed to safely divert an electrical charge.

Using nitrogen blanketing would be the company's next step, Casten said. The company is constructing a nitrogen system at its 31-tank facility in Kansas City, Kan.

"We want to install one and see how it works," he said.

Besides enhancing safety, a nitrogen system also decreases solvent emissions, he said.

If the nitrogen system at Kansas City passes the test, it would be installed companywide, he said.

One option for Barton Solvents, if it doesn't rebuild in Valley Center, is opening a tank farm in Bel Aire, near 53rd and Greenwich. The Bel Aire site would allow for more of a buffer zone, Casten said.

Wherever Barton Solvents puts its new tank farm, it would have about 40 tanks, Casten said. He hopes a new tank farm could open in about eight months.